1. Field of the Invention
The invention relates to a novel preserving system comprising a combination of at least one C.sub.1 -C.sub.4 alkyl para-hydroxybenzoate with sodium benzoate and N-(3-chloroallyl)hexaminium chloride. The invention also relates to the use of this novel system in the cosmetic and pharmaceutical fields, and in particular in compositions intended to be applied to the face and the eyes of mammals and in particular of human beings. These compositions are more especially cleansing lotions for the face and the eyes.
2. Discussion of the Background
It is common to introduce into compositions containing water, such as cosmetic or pharmaceutical compositions, in particular dermatological compositions, chemical preserving agents intended to combat the growth and proliferation of microorganisms in these compositions since such a growth of micro-organisms would rapidly make the compositions unsuitable for use. To avoid this growth, the compositions should be protected both against micro-organisms capable of growing inside the compositions and against those which the user might introduce therein when handling them, in particular when the products are taken from a jar by the fingers.
The chemical preserving agents most commonly used in the above fields are, in particular, C.sub.1 -C.sub.4 alkyl para-hydroxybenzoates, referred to hereinbelow as parabens, or formol donors. Unfortunately, these preserving agents have the drawback of causing intolerance on human skin, such as irritations and/or allergies, and more especially on sensitive skin. This is likewise the case for alcohols or polyols, such as ethanol or propylene glycol, in particular when they are present at relatively high levels. These problems of intolerance arise most particularly when the products containing these preserving agents are cleansing products and make-up-removing products for a person's face and eyes.
Moreover, it is known to use in cleansing products for the skin and the eyes, and in particular in make-up-removing lotions for the eyes, preserving agents such as benzalkonium chloride, chloroacetamide or thimerosal. Thus, document WO-A-94/27436 teaches a preserving system comprising a paraben and a quaternary ammonium compound such as benzalkonium chloride or cetylpyridinium chloride. However, the current trend and the legislation pertaining thereto are increasingly changing towards the elimination of these compounds since they are not entirely free of toxicity or of undesirable effects.
In addition, document D&CI, May 1986, 138 (5), incorporated herein by reference, at pp. 50, 52-55, and 61 describes the use of N-(3-chloroallyl)hexaminium chloride, referred to hereinbelow as Quatemium-15, as a cosmetic preserving agent and its combinations, in particular with parabens. However, the systems described in that document have the drawback of containing excessively high levels of Quatemium-15 (0.4%), which leads to eye discomfort (runny eyes, stinging, dryness, itching, redness) or allergies.